package app.champaign;

public class L101_SymmetricTree{


    public static void main(String[] args) {
        
    }

    public static boolean isSymmetric(TreeNode root) {
       return isMirror(root, root);    
    }

    public static boolean isMirror(TreeNode t1, TreeNode t2){
         //corner case
        if (t1 == null && t2 == null)
            return true;
        if (t1 == null || t2 == null)
            return false;
        return (t1.val == t2.val) && isMirror(t1.right, t2.left) && isMirror(t1.left, t2.right);
    }

    

}